A recent study by the National Association of Realtors revealed that home prices have gone up due to limited supply. The study also found that four out of the five most expensive metros in the U.S. for the first quarter of 2015 are located in California.

Report's findings

The national median existing single-family home price in 2015 Q1 was $205,200, a 7.4 percent year-over-year jump from $191,100 of 2014 Q1, notes the NAR.

The largest trade association explains that the total existing-home sales dropped 1.8 percent to a seasonally adjusted annual rate of 4.97 million in 2015 Q1, from 5.06 million 2014 Q4. It also states that at the end of the first quarter, only 2.00 million existing homes are available for sale, showing an unhealthy 4.6 months supply, with six to seven months considered as healthy supply for buyers and sellers.

The very limited inventory resulted to home prices accelerating during the first quarter of the year, and "the number of areas posting double-digit price appreciation doubled" compared to the 2014 Q4, the NAR adds. In fact, 148 out of 174 metros, equivalent to 85 percent of these markets, posted home appreciation.

Lower median prices

The NAR also identified 25 areas with lower median prices.

Of those areas which experienced home appreciation, 51 (28 percent) had double-digit increases, a pronounced hike from 24 metro areas in the 2014 Q4 exhibiting the same. It was larger compared to the 37 (22 percent) which showed double-digit increases in 2014 Q1, or exactly a year ago.

Lawrence Yun, NAR chief economist explains the change from healthier levels of growth at the 2014 Q4 to the recent data, where prices picked up in many metros during 2015 Q1.

"Sales activity to start the year was notably higher than a year ago, as steady hiring and low interest rates encouraged more buyers to enter the market," Yun said. "However, stronger demand without increasing supply led to faster price growth in many markets."

"Sales could soften slightly in some of these markets seeing sharp price appreciation unless housing supply markedly improves and tempers its unhealthy level of growth," adds Yun in the report.

Here are the current five most expensive metros in the country, based on the NAR report, with their corresponding median existing single-family price:

1. San Jose, California, $900,000

2. San Francisco, $748,300

3. Honolulu, $699,300

4. Anaheim-Santa Ana, California, $685,700

5. San Diego, $510,300

All these places posted median home prices above $500,000, almost eight times the value of median home prices in the least expensive metro, Ohio.

On the flip side, here are the five least expensive metros showing each metro's median existing single-family price:

1. Youngstown-Warren-Boardman, Ohio, $64,300

2. Cumberland, Maryland, $71,600

3. Rockford, Illinois, $78,600

4. Decatur, Illinois, $82,200

5. Toledo, Ohio, $83,800

From the data, all five places had median home prices posting below $85,000, with all the five spots coming from Ohio, Illinois or Maryland.